Electric incandescent device



f r H Is At or-ney.

G R FONDA ELECTRIC mcmnsscnu'r DEVICE Filed August 30 1924 Ira/enter:

Gorton R. Fonda, by

July 27 1926. Q

UNITED STATES PATENT OFFICE. c

Genre! :a. son, or m, saw 203:, assrouoa 'ro emu. mcrarc comm, a OOBPOBA'I'IOI or new You mt! DEVICE.

Application fled August 80, 1984- Serial I0. 735,074.

The present invention relates to devices containing a filament or other body rating at incandescence and in particul; to

I electric lamps containing a ttmgsten fila I ment.

It is the object of my invention to increase the resistance of incandescent bodies to the disintegrating efiect of high temperature 0 ration. In fill lamps sarticularly, the fail- ,ure 0 the filament is ue usually to a local disintegration rather than to a uniform wasting away along its entire length. I have found upon the examination of many' burned-out lamps that *a dis lacement or lsh'spage within the crystals 0 the filament occurred, particularly near the supports. aids minutethsca lg utihis dispflacemiant is]:

ogousto e a ting" o geoogic "strata. This slfipage of crystal planes over each'other sho not be confused with the oil-setting spect to each other. It is ap arently due to this faulting in the cry that 1n the 55 average gas-filled lamp the li hting fila-. ment fails when its decrease 0 weight by volatilization is only about one-third of the average loss of weight which a filament in.a vacuum lamp will withstand before failure occurs.

I have {liscovered thatthis faulting of the crystal p anesin tungsten bd ice at incandescence may be ve substantially reduced and for-a given efiiciency the life of a filament will be lengthened correspondingly by introducing into the filament a small quanti of zirconium. e zirconium alloy thus formed also has a'lower vapor presure than ttmgsten whlch son the filament can be operated with a lo r average life at a' given efliciency or wi a hi her eflicienc at a given life 1n a vacuum amp, as we as in a gas-filled lamp. In, the latter case the improvement either in efliciency or in length of life, de-' pending on the operating conditions, is most marked as the lower volatility of the m tunegsten-zirconium'alloy as compared with A un loyed tungsten and the decrease 1n tendency to faulting in the crystal both benefit the operation of the lamp.

In m r'ior application Ser. No. 399,- 798, filed fuly 29, 1920, I have described the introduction of zirconium into a lighting of crystals as a whole with re-- does not contain For this rea- I body by a rooms involving the coating of a tungsten ament before its introduction mto a lamp bulb with a layer of zirconium, the alloyage of diffusion .of the zirconium mto the'interior of the filament occurring subsequently at a hiher temperature. In this case the filament its operation in a lamp or other device with a maximum zirconium content which is ually decreased by evaporation at incan escence.

- In accordance with my present invention the zirconium as an allo constituent is obtained from a source provi ed in the lamp bulb and the zirconium is introduced into the tungsten body by a diiferent method, namely, the progremivethermal decomposition of the va r of a zirconium com und which comes mto contact with the mcandescent body at low pressure, accompanied by immediate alloyage of the liberated zirconium with the tungsten. This gradual decomposition of the zirconium and the al-; loyage of zirconium is a proces which fishes on d the entire life of the lamp. e advantage of this continuous alloyage will be later explained The accompanying drawing shows in Fig. 1 an incandescent lamp having a hollow stem containing a zirconium compound; Fi 2 shows a vacuum lamp containing 1 y a zirconium compound and Fig. 3 illustrates a modification in which the zirconium com pound is applied on a filament support.

The lamp shown in 1 comprises the usual sealed bulb 1 containing a 1: filament 2, wound in a spiral too :m 1 and close to be here illustrated, in such way as to give the effect ofa larger diameter The filament is mounted upon anchor wires 3, 4, which in turn are carried b a glass stem 5. As shownin section at ebase of the lamp, the bulb is exhausted during manufacture through a tube 6, which after exhaust is sealed ofi. The lamp is provided as usual with a base 7, which is cemented in place as indicated at 8. P

In the tube 6 is provided a capsule 9 containin a zirconium compound, preferably the ch oride, ZrCL. This capsule is introdnced through the exhaust tube 6 during the manufacture of the lamp and is held m place by glass wool 10 as illustrated. The amp contains a gas, such as argon or mtrogen at substantial pressure, say at 600 m. m. of mercury to reduce evaporation of the filaa placed looselywithin "b ment in accordance with uir U. S. Patent 1,180,159, issued April 18, 1916.

As already stated the benefits of my invention are not confined to an incandescent lamp which is charged with an inert gas. Fig. 2

shows an incandescent lamp of the vacuum type in which a tungsten filament 11 is wound in zig-zag manner over two sets of anchors 12, 13 which'are in turn mounted spaced apart upon-a glass pedestal 14. The filament is mounted in the well known manher in an evacuated'bulb'lti and is electrical- 7 1y connected to theicontacts'of an external screw base 16. theevacuated bulb is provided a of zirconium compound which placed within a receptacle as shown fm?;Fig. 1 or may be ulb as shown at Other ways of locating the zirconium compound may be devised to the benefits of my inventionr-iForexample, as shown in Fig, 3, a smallquantity ofgthe zirconium compolmd together with a suitable binder conium chloride or other halogen compound of zirconium, the material knownas film stock, comprising a compound of cellulose,

such as cellulose acetate, may be used. The

zirconium compound may be present to the amountof a few milh An excess is allowable as only the vapor of. the compound comes into contact with the filament.

As zirconium chloride has alow vapor premure it may be placed almost anywhere, either in a'gas filled or in a, vacuum lamp, except in direct contact with the filament. When placed upon some part of the lamp having during operation a temperature not substantially higher than the temperature of. the bulb. the vapor of the zirconium compound will have a pressure not substantially greater than the residual-gas pressure in a first-clas vacuum, that is, a presure of less than a micron of mercury. Due to this'small vapor pressure the zirconium is supplied to the filament continuously in such 'small amounts as to compensate for the zirconium which is lost by evaporation at the operating temperature-of the filament. In other words due to the low vapor pressure of the zirconium chloride an equilibrium is established between the incandescent filament and the zirconium chloride vapor which comes in contact it,so that alow but substantially constant content of zirconium is maintained in the filament The zirconium content producedin the filament does not exceed a few per cent and probably less than. two' per cent, It is diificult to determine the exact amount in so small a mass which is tungsten during the life of the lamp as w as gaining zirconium.

The zirconium atoms pear to have a function of preventing shp of crystal planes by a-keying action, that is the solid solution of tungsten and zirconium is formed in different parts of the er stal' and the difierence in atomic size of t is in the tungsten ap I solid solution serves as a key to prevent dis lacement of crystal planes e zirconium compound acts in the nature of a getter to continuously deposit on the filament in small amounts a substance (that is zirconium), which acts beneficially to maintain the filament intact when operating at inoandescence, both by reduc' the vapor pressure and by. counteractin aul 4 ing. In devices, suc as gas-fill lam s both functions are of marked benefit.

improvement in life at a given efliciency has been found to be of the order of magnitude of fifty per cent. Although described with.

articular reference to electric lamps my invention is applicable in' general to devices in which a body of tungstenis operated at incandescence and I wish it to be understood that the accompanying claims are intended to include devices, other than lamps presenting the described conditions.

' .What I claim as new and desire to secure by Patent of the United States, 1s: a g

1; An incandescent lamp comprising a sealed bulb, a tungsten filament therein, and

a zirconium compound which is decomposa-- ble atincandesence located in said bulb outside of the immediate vicinity of the filament and having at the temperature prevailing at the region of location a vapor pressure not. greater substantially than the residual ressure in a first-class vacuum.

2. candescent lamp comprising a sealed bulb, a -fi1ament mounted therein, and zircomum chloride positioned insaid bulbtoattainatem 'turea'twhich' the .vapor pressure of sai compound is of the order of: the reddual gas pressure of a first-class vacuum. 2. An incaggescent lampcomprising a bulb, a tungst filament'therein, and means for supplying to said filament during the mcandescence thereof in: such' measure that a zirconium content not exceeding a few per cent is maintained filament during the life ofthe lamp,

4. The method of preserving a incandescent body when operating at temin said Ill peratures at which volatilizationis substantial'which consists in supplying into contact with said body the vapor of zirconium chloride at a pressure not substantially highcthan the residual gas pressure of a firstas vacuum. f

5. The method of reducing the volatilizaon of a hmfisten filament in an incandesmt lamp w ich consists in continuously lppl zirconium to said filament while lcan eacent at such rate that the zirconium intent of said filament is maintained no reater than a few per cent.

6. The method 0 reduc' the volatilizaon and crystal faulting o a tungsten incandescent body in a lamp containing an inert gas at substantial ressure which consists in operating said fiody in contact with the vapor of zirconium chloride at a pressure corresponding to the vapor pressure of said compound at substantmll the operating temperature of the lam ulb.

In witness whereof, I have ereunto set my hand this 28th day of August, 1924.

GORTOIN R. FONDA. 

